Flash exposed pre-inked stamps have been made by printing or otherwise photographically imaging a positive or negative image on a transparent indicia medium, such as paper or plastic, then placing that image on a transparent body of typically glass or plastic in between a light source and the micro-porous material to be exposed. On top of the transparent indicia medium could be a clear protective sheet and then the flash exposable micro-porous material. The micro-porous material then could be compressed to form a compressed surface at the exposure surface. This process is known in the industry under the trademark, “Ultimark.”
A disadvantage of this system is that the exposable micro-porous foam must be manually aligned with the indicia to be exposed (i.e., the image or text to appear on the stamp). This requires a careful worker with adequate time. It also results in possible misalignment and/or low manufacturing efficiencies. While this may not be a significant problem with low volume producers who may make up to 20 or more stamps per day with a steady and semi-skilled workforce, it is disadvantageous for large volume producers. Manufacturers producing high volume stamps require a more foolproof and cost efficient system of manufacturing.